Effective Mass Research Articles

Flavor Hierarchy of Jet Energy Correlators inside the Quark-Gluon Plasma

Heavy flavor jets provide ideal tools to probe the mass effect on jet substructure in both vacuum and quark-gluon plasma. An energy-energy correlator (EEC) is an excellent jet substructure observable owning to its strong sensitivity to jet physics at different scales. We perform a complete realistic simulation on medium modification of heavy and light flavor jet EECs in heavy-ion collisions. A clear flavor hierarchy is observed for jet EECs in both vacuum and quark-gluon plasma due to the mass effect. The medium modification of inclusive jet EECs at different angular scales exhibits a very rich structure: suppression at intermediate angles, and enhancement at small and large angles, which can be well explained by the interplay of mass effect, energy loss, medium-induced radiation, and medium response. These unique features of jet EECs are shown to probe the physics of jet-medium interaction at different scales, and can be readily validated by upcoming experiments. Published by the American Physical Society 2025

BSN-I: The First In-Depth Photometric Study of Seven Total Eclipse Contact Binary Systems

Abstract This is the first in-depth study of seven total-eclipse W Ursae Majoris (W UMa)-type contact binary systems using photometric light curves. The ground-based observations were conducted with four observatories in the northern and southern hemispheres. We also used the Transiting Exoplanet Survey Satellite (TESS) for four target systems. We presented the analysis of orbital period variations of six systems and found that they display parabolic variations. The material transfer rates between the stars of the systems were calculated. Also, the results show that four systems have a long-term increase, while two have a long-term decrease in their orbital periods. We analyzed light curves using the PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the Markov Chain Monte Carlo (MCMC) algorithm to estimate different parameters of target systems and their uncertainties. Six of the target systems required the addition of a cold or hot starspot. We estimated absolute parameters using the empirical relationship between the orbital period and the semi-major axis (P − a). According to each component’s effective temperature and mass, it was recognized that the studied systems are W-subtype. We examined the dynamic stability of two targets, which were low mass ratio contact binary systems. We also showed the evolution of stars in the M − R and M − L diagrams. Finally, we showed that the hotter stars in contact systems have a temperature difference of less than ≈400 K compared to the Gaia DR3 temperature report.

Impact of electric field on donor energy and polarisability in GaAs variant toroidal quantum ring

ABSTRACT This study investigates the electronic properties of a GaAs Variant Toroidal Quantum Ring (VTQR) containing an off-centre donor impurity, focussing on the effect of an external electric field on donor energy and polarisability. Based on the effective mass approximation, we solved the Schrödinger equation using the finite difference method. The results show a typical effect at a toroidal angle of 180 ∘ , where the strength of the electric field leads to a decrease in the donor energy. Intriguingly, at toroidal angles of 90 ∘ and 60 ∘ , the donor energy increases with increasing field strength, indicating improved electron confinement. The probability density distributions shown reveal the location of the electron as influenced by the applied field. Furthermore, polarisability reaches its maximum around an angle of about 80 ∘ for all electric field strengths. This work provides a better understanding of the behaviour of electron in quantum ring systems and suggests potential for the engineering of tunable quantum devices.

Influence of Effective Nucleon Mass on Equation of State for Supernova Simulations and Neutron Stars

Abstract We investigate the influence of the effective nucleon mass on the equation of state (EOS), which is constructed for simulations of core-collapse supernovae and binary neutron star mergers, within the relativistic mean-field (RMF) framework. The study introduces a new RMF parameter set, TM1m, which is a modification of the TM1e model with an adjusted effective mass, maintaining the saturation properties of nuclear matter. The TM1m model, with a larger effective mass ratio (M */M ~ 0.8) compared to the TM1e model (M */M ~ 0.63), is employed to construct a new EOS table, EOS5. This EOS table is designed to offer insights into the influence of the effective nucleon mass on the EOS within a relativistic framework, particularly above the saturation density. The results of EOS5 are compared with those obtained from other models, including both relativistic and nonrelativistic approaches. The properties of cold neutron stars, calculated using the TM1m model, are compatible with the existence of a 2 M ⊙ pulsar and the latest constraints on the tidal deformability and radii of a canonical 1.4 M ⊙ neutron star, derived from astrophysical observations.

Masses and Magnetic Moments of Singly Heavy Pentaquarks using the Gursey-Radicati Mass Formula, Effective Mass, and Screened Charge Scheme

Masses and Magnetic Moments of Singly Heavy Pentaquarks using the Gursey-Radicati Mass Formula, Effective Mass, and Screened Charge Scheme

METHODS FOR CALCULATING THE PARAMETERS OF SURFACE VIBRATING MACHINES FOR COMPACTING BUILDING MIXTURES

The paper developed methods for calculating the main parameters of surface vibrators, installations, and vibratory rollers based on the study of a mixed discrete-continuous model of the system “machine working body - compacting medium”. The calculation algorithms are based on a preliminary definition of the choice of the type of machine depending on the type of compaction process, the composition of the mixture, and the justification of modes and parameters. The numerical values of the evaluation criteria are proposed to ensure effective and energy mass, power, and energy indicators. The calculation methods provide for both resonant and resonant modes of operation of vibrating machines. The results obtained open the way for the design of vibrating machines and other structures of this class.

Black Hole Supernovae, Their Equation of State Dependence, and Ejecta Composition

Abstract Recent literature on core-collapse supernovae suggests that a black hole (BH) can form within ∼1 s of shock revival, while still culminating in a successful supernova. We refer to these as BH supernovae, as they are distinct from other BH formation channels in both timescale and impact on the explosion. We simulate these events self-consistently from core collapse until 20–50 days after collapse using three axisymmetric models of a 60 M ⊙ zero-age main-sequence progenitor star and investigate how the composition of the ejecta is impacted by the BH formation. We employ Skyrme-type equations of state (EOSs) and vary the uncertain nucleonic effective mass, which affects the pressure inside the proto–neutron star through the thermal part of the EOS. This results in different BH formation times and explosion energies at BH formation, yielding final explosion energies between 0.06 and 0.72 × 1051 erg with 21.8–23.3 M ⊙ of ejecta, of which 0–0.018 M ⊙ is 56Ni. Compared to expectations from 1D simulations, we find more nuanced EOS dependences of the explosion dynamics, the mass of the BH remnant, and the elemental composition of the ejecta. We investigate why the explosions survive despite the massive overburden and link the shape of the diagnostic energy curve and character of the ejecta evolution to the progenitor structure.

Energy Distribution Effect on Bremsstrahlung Radiation Produced by \(B_{11}^{5}\) and \(Al_{27}^{13}\)

By using the Bethe-Heitler equation, this work determines the energy distribution of Bremsstrahlung radiation for \(B_{11}^{5}\) and \(Al_{27}^{13}\). We utilize the mathematical program "Mathematica" to contrast the electromagnetic impacts of photons resulting from interactions of electrons with boron and aluminum nuclei. We compare the effects of electric and magnetic cross-sections on the generation of Bremsstrahlung radiation. We will examine the impact of electric and magnetic fields on the production of Bremsstrahlung radiation using graphs. We also investigate the effect of atom mass on the emission of Bremsstrahlung radiation. According to our results, certain types of X-rays can be produced by using magnetic interactions.

Exoplanet Occurrence Rate with Age for FGK Stars in Kepler

Abstract We measure the exoplanet occurrence rate as a function of isochrone and gyrochronology ages using confirmed and candidate planets identified in Q1–17 DR25 Kepler data. We employ Kepler's pipeline detection efficiency to correct for the expected number of planets in each age bin. We examine the occurrence rates for planets with radii 0.2 ≤ Rp ≤ 20 R ⊕ and orbital periods 0.2 ≤ P ≤ 100 days for FGK stars with ages between 1.5 and 8 Gyr using the inverse detection-efficiency method. We find no significant trend between the occurrence rate and stellar age; a slight decreasing trend (within 1.5σ–2.5σ) only emerges for the low-mass and metal-rich stars that dominate our sample. We isolate the effects of mass and metallicity on the occurrence rate trend with age, but find the results to be inconclusive, due to weak trends and the small sample size. Our results hint that the exoplanet occurrence rate may decrease over time due to dynamical instability from planet–planet scattering or planet ejection, but accurate ages and larger sample sizes are needed to resolve a clear relation between the occurrence rate and age.

Valley-Contrasting Linear Dichroism and Excitonic Condensation in LaOBiS2.

In conjunction with the first-principles calculations, we confirm the fascinating valley-selective linear dichroism and the possibility of excitonic condensation in multiatomic-layer LaOBiS2 of a tetragonal lattice by the effective tight-binding model and many-body perturbation theory. In LaOBiS2, which indicates a spontaneous valley polarization due to crystalline symmetry reduction rather than conventional time-reversal symmetry breaking, we unravel that the excitons in X and X' valleys exclusively coupled to x- and y-linearly polarized lights, respectively. In sharp contrast to coupled quantum wells and van der Waals architectures, a new type of spatially indirect exciton is identified in single-crystal LaOBiS2, manifesting itself as an engaging platform for investigating the excitonic Bose-Einstein condensation (BEC) and superfluidity. In light of large binding energy, large radius, and small effective mass of the exciton, the transition temperature for BEC and superfluidity achieves record-high values of 325.1 and 81.3 K, respectively.

Investigation on phase formation and thermoelectric transport properties of CoTe2-CoSe2 solid solution alloys.

CoTe2 and CoSe2 alloys have garnered considerable attention in thermoelectric applications due to their high electrical conductivity, tunable electronic properties, and potential for high power factors. In this study, the phase formation behavior and thermoelectric transport properties of a CoTe2-CoSe2 solid solution alloy were investigated by synthesizing a series of Co(Te1-xSex)2 compositions, where x = 0, 0.25, 0.50, 0.75, and 1.0. For x = 0, 0.25, and 0.50, the orthorhombic phase of CoTe2 was observed, while for x = 0.75, the orthorhombic phase of CoTe2 and cubic phase of CoSe2 coexisted. Up to x = 0.50, the power factor decreased slightly as the Hall mobility and the density-of-state effective mass decreased. The total thermal conductivity decreased as x increased to 0.50, owing to a decrease in the electronic and lattice thermal conductivity. Despite the decrease in total thermal conductivity, no significant increase in zT values was observed in the range of x = 0.25-0.50 due to a more pronounced decrease in the power factor. Nevertheless, cubic phase CoSe2 exhibited higher power factors and thus higher zT of 0.13 at 700K. Further analysis based on single Kane band model suggests that significant enhancement in the power factor and zT could be achieved by reducing the carrier concentration from ∼1021 to ∼1019 cm-3 for all compositions.

Radiative properties and QPOs around charged black hole in Kalb–Ramond gravity

Studies of accretion disc luminosities and quasiperiodic oscillations around black holes may help us understand the gravitational properties of black hole spacetime. This work is devoted to studying the radiation properties of the accretion disk around the black holes in Kalb–Ramond gravity. We investigate the event horizon of the black hole spacetime and calculate the effective gravitational mass of the spacetime. Also, we analyze the circular motion of test particles in the black hole spacetime. The effects of the black hole charge and KR parameters on the particles’ effective mass, energy, and angular momentum at circular orbits and innermost stable circular orbits are studied. The frequency of Keplerian orbits and the radial and vertical oscillations of the particles along stable orbits are calculated and applied to analyze the existence of QPO in relativistic precession, warped disc, and epicyclic resonance models. QPO orbits’ locations with ratios of upper and lower frequencies of twin-peaked QPOs 3:2, 4:3, and 5:4 are analyzed compared to ISCO. We also obtain constrain values for the black hole mass, charge, KR field parameter, and QPO orbits found using Markovian chain Monte Carlo (MCMC) simulations for stellar mass (XTE J1550, GRS 1915+105), intermediate mass (M82-X1), and supermassive black holes (Sgr A*). Finally, we explore the radiative properties of the accretion disk around the charged black hole in KR gravity, such as the total radiation flux, accretion disc temperature, and differential luminosity.

Bound and Continuum Intersubband Transitions in Colloidal Quantum Wells.

Quantum well intersubband transitions are critical for quantum cascade lasers and infrared photodetectors. Control of band offsets allows bound-to-bound intersubband transitions, with confinement of both initial and final states, and bound-to-continuum transitions, in which only the initial state is energetically confined within the potential well. Both types of transitions are also achieved in colloidal CdSe wells by changing the heterostructure shell. Bare wells have narrow intersubband transitions spanning the near-infrared spectrum following effective mass predictions. Atomically precise core/shells enable a readily adjusted potential well for electrons. For CdSe/ZnS, bound-to-bound transitions are narrow and redshift with shell thickness. By contrast, broad bound-to-continuum absorptions are found in CdSe/CdS. Due to small conduction band offsets, higher conduction band states of the well are more delocalized into the CdS shell. These measurements provide unique data to understand the electronic structure of colloidal quantum wells and chart a path to atomically precise optoelectronic materials for the mid-infrared.

Phononic band gaps of photonic crystals with inverse opal structure

We studied theoretically the phononic band gaps (PnBGs) of photonic crystals (PhCs) with an inverse opal (IO) structure based on trimethylolpropane ethoxylate triacrylate (ETPTA). These crystals consist of closely packed spherical voids ∼260 nm in diameter filled with water and metals. Dispersion dependencies for the main characteristics (dispersion curves, group velocity of phonons, and effective mass of phonons) of the studied samples have been constructed. Filling the voids of PhCs with various materials demonstrated the ability to tune the width and center of PnBGs. The obtained results open avenues for potential applications of such hypersonic photonic nanostructures, including tunable sensors, filters, heat management systems, and acoustic-optical devices.

Abstract TMP71: Delineating the Evolution of the Immune Response in Peripheral Blood, Hematoma and Peri-hematomal Brain of Intracerebral Hemorrhage Patients

Background: Intracerebral hemorrhage (ICH) is the second most prevalent type of stroke, but carries the greatest degree of mortality and morbidity. In addition to the primary injury due to mechanical stress and mass effect on adjacent brain regions, uncontrolled inflammation in the peri-hematomal area constitutes a secondary insult that can exacerbate tissue damage, leading to cerebral edema, neuronal death, and thus worse clinical outcomes. Prior efforts at controlling ICH-related inflammation reported mixed outcomes, likely reflecting our poor understanding of the evolving inflammatory cascade following ICH. In this investigation we sought to better characterize the cellular immune response in the acute period following ICH. Methods: Surgical candidates for minimally invasive hematoma evacuation were approached for participation in this study. We collected evacuated clots, and small biopsies from peri-hematomal brain, and matched peripheral blood immediately preceding surgical evacuation, and on days 1, 3, and 5-7 post-surgery. We then isolated all immune cells from each compartment and performed transcriptomic profiling by single cell RNA-sequencing, from 6 patients operated on at time points ranging from 4 to 29 hours after time of last known well. Results: Data from 5 male and 1 female patient 46-79 years old are reported. Our data analyses showed an evolving inflammatory cascade consisting primarily of neutrophils and macrophages that is very similar in the blood and clot compartments. Importantly, the time elapsed between ICH incidence and surgical evacuation is positively correlated with the emergence of an inflammatory osteopontin-expressing macrophage population in the blood clot, and a unique microglial signature in the peri-hematomal brain. We also found that the presence of a fibrin-laden blood clot in the brain initiates an early and evolving gene signature in neutrophils and microglia in the brain parenchyma, that is distinct from the inflammatory responses identified in peripheral blood. Conclusions: Our findings show that rapid surgical evacuation of the hematoma within the first 4-5 hours limits the inflammatory insult, and highlight key immune cell populations involved in the inflammatory response post-ICH. We also identified key pathways driving these inflammatory responses, thereby providing novel potential therapeutic targets for patients with ICH.

The associations of body composition, fitness, and physical activity with balance in children: The Arkansas Active Kids study.

Balance plays an important role in children's motor development. However, the factors that are associated with balance in children are not yet fully understood. We aimed to investigate the association of body composition, physical fitness, and daily physical activity on balance in children. The sample was composed of 219 children (53 % females), aged 9.0 (IQR = 2.2) years with a body mass index (BMI)-percentile of 74.9 (IQR = 48.7). Balance was evaluated through a force platform in the upright bipedal stance under different sensory conditions. Anthropometry, body composition (dual-energy x-ray absorptiometry), knee maximal strength (isokinetic dynamometer), aerobic capacity (indirect calorimetry), and daily physical activity (accelerometry and questionnaires) were also assessed. Higher levels of body mass, waist circumference, and fat mass were associated with worse balance, whereas greater knee extension strength and peak oxygen uptake were linked to enhanced balance. Among those, fat mass percentage and waist circumference were the most important factors associated with balance performance. Moreover, it was observed that the associations between the identified anthropometric and body composition measures with balance could be counteracted by physical fitness and physical activity levels. Our findings revealed that anthropometric measures, body composition, and physical fitness levels are associated with children's balance. Furthermore, physical fitness and physical activity may be especially relevant, as they could help mitigate the detrimental effect of excess fat mass on postural control.

Visible light-driven copper vanadate/biochar nanocomposite for heterogeneous photocatalysis degradation of tetracycline: Performance, mechanism, and application of machine learning.

Water pollution caused by antibiotics is considered a major and growing issue. To address this challenge, high-performance copper vanadate-based biochar (CuVO/BC) nanocomposite photocatalysts were prepared to develop an efficient visible light-driven photocatalytic system for the remediation of tetracycline (TC) contaminated water. The effects of photocatalyst mass, solution pH, pollutant concentration, and common anions on the TC degradation were investigated in detail. Analytical techniques indicated that the CuVO exhibited a nanobelt-like structure with a uniform distribution on the wrinkled biochar surface. The XRD spectrum confirmed that the as-prepared nanomaterial was composed of Cu3V2O7(OH)2·2H2O. Meanwhile, XPS analysis revealed that copper was present in two forms: monovalent and divalent, while vanadium remained pentavalent. The CuVO/BC exhibited excellent stability and high visible light photocatalytic activity towards TC degradation over a wide pH range. The presence of SO42-, H2PO4-, CO32-, and citric acid inhibited the degradation process due to the consuming of photogenerated h+ and •OH, while Cl- enhanced the efficiency of photocatalytic reactions due to generating chlorine oxidizing species. The CuVO/BC showed lower electron-hole recombination rate, more effective separation of photogenerated carriers, lower charge transfer resistance, and higher visible light absorption capacity comparing to pure CuVO by the addition of BC, thus improving the overall photocatalytic performance. In terms of oxidation mechanism, the EPR test and quenching experiment revealed that the contribution of the active species to the degradation of TC followed the order h+ > 1O2>•OH>•O2-. Through the application of machine learning models to analyse the influencing factors of photocatalytic processes, it was discovered that the GBDT model exhibited optimal reliability for the photocatalytic system, and the simulation results were in agreement with the experimental findings.

Unique considerations in the assessment and management of traumatic brain injury in older adults.

The age-specific incidence of traumatic brain injury in older adults is rising in high-income countries, mainly due to an increase in the incidence of falls. The severity of traumatic brain injury in older adults can be underestimated because of a delay in the development of mass effect and symptoms of intracranial haemorrhage. Management and rehabilitation in older adults must consider comorbidities and frailty, the treatment of pre-existing disorders, the reduced potential for recovery, the likelihood of cognitive decline, and the avoidance of future falls. Older age is associated with worse outcomes after traumatic brain injury, but premorbid health is an important predictor and good outcomes are achievable. Although prognostication is uncertain, unsubstantiated nihilism (eg, early withdrawal decisions from the assumption that old age necessarily leads to poor outcomes) should be avoided. The absence of management recommendations for older adults highlights the need for stronger evidence to enhance prognostication. In the meantime, decision making should be multidisciplinary, transparent, personalised, and inclusive of patients and relatives.

Crossed Brainstem Syndrome of the Tectal Plate's Inferior Colliculus Revealing Quadrigeminal Midbrain Cavernous Malformation

Cavernous malformations are low-flow fragile vascular lesion, prone to extralesional bleeding that can occur in the cerebral hemispheres, the brainstem, or the spinal cord. We report the case of a 32-years-old right-handed male patient with acute-onset headaches associated with right-sided tinnitus, right-sided hemianesthesia, and binocular diplopia related to cranial nerve IV palsy. Neuroimaging displayed left-sided isolated cavernous malformation of the inferior tectal plate, with evidence of extralesional bleeding. Clinical presentation and neuroimaging features were compatible with inferior colliculus crossed brainstem syndrome. Thanks to clinical improvement and the absence of mass effect on neuroimaging, surgical intervention was delayed. At the 3 months follow-up consultation, symptoms had improved aside from diplopia which required wearing prism eyeglasses. Tectal cavernous malformations account for 18% of midbrain cavernomas. It was explained that surgical excision using the supracerebellar infratentorial approach would be performed within 2 months following a second extralesional bleeding episode causing disabling symptoms.

Metastatic Hobnail Papillary Thyroid Carcinoma Initially Diagnosed by Pleural Effusion: Case Report of a Rare and Intriguing Entity.

Hobnail papillary thyroid carcinoma (HNPTC) is an unusual and aggressive variant of PTC. Malignant pleural effusion secondary to thyroid carcinoma is a rare event reported in less than 1% of cases. Herein we present a case of metastatic HNPTC initially diagnosed by pleural effusion cytology, with a very poor outcome. A 42-year-old male with no previous cancer history, presented with an anterior neck mass growing for the past year. A computed tomography (CT) scan revealed a large complex cystic lesion with mass effect on the anterior thyroid gland, along with multiple neck and mediastinal necrotic lymph nodes, suspicion for metastasis. CT of the thorax showed lung nodules and a large left pleural effusion. Fluid was drained and sent for cytologic examination which revealed malignant cells predominantly in a micropapillary pattern with apically placed, bulged, "hobnail-like" appearance; intranuclear pseudo-inclusions or chromatin clearing was not seen. Based on cytomorphologic findings and immunohistochemical results (CK7 and PAX-8 positive; TTF-1, Napsin-A, and mesothelial markers negative), final diagnosis of HNPTC metastatic to pleural fluid was made. Fine-needle aspiration of neck mass showed similar cytomorphologic findings, confirming a thyroid origin. However, the patient experienced complications, rapid deterioration and died 6 months after diagnosis. The intersection of clinical-radiologic findings, cytology, and immunohistochemistry guided the identification of this rare variant of PTC as the origin of the malignant pleural effusion. We believe this case provides a valuable insight into the complexities involved in the diagnosis of thyroid carcinoma and emphasizes the significance of proper identification of rare variants.